The accused Aurora gunman reportedly spat at jail officers so often that he was forced to wear a spit guard at one point.

Holmes’ bizarre habit is just one of several that he has displayed since his arrest for the shooting rampage during a midnight screening of The Dark Knight Rises in a Colorado movie theater that killed 12 and wounded 58 last Friday.

In the hours after his arrest Friday for the massacre at the Aurora, Colo., movie theater, Holmes stared at the wall in the Arapahoe Police Headquarters with his eyebrows twitching.

Then, Holmes allegedly told police he was Batman’s villain the Joker. When cops put evidence bags over his hands to preserve traces of gunpowder residue, he pretended the bags were puppets, law enforcement sources told ABC News affiliate KMGH-TV in Denver.

The public got its first glimpse into his behavior during his court appearance Monday, where he looked alternately dazed and bug-eyed while occasionally nodding with his eyes appearing to close. Holmes is unmissable, currently sporting a head of bright-orange dyed hair — which he reportedly told authorities he dyed to look like the Joker villain in Batman films, even though the Joker’s hair is typically green.

And now, Arapahoe County Jail officers told ABC News that Holmes spits at them so much that they have to use a spit guard on Holmes while moving him. These antics are just the latest in findings that contradict the initial profile of him as an unassuming former graduate student.

Marissa Randazzo, former chief research psychologist for the U.S. Secret Service and an expert in mass shootings, told Good Morning America today that there are several possible explanations for Holmes’ recent behaviors. “One is that he is in the middle of a psychotic episode which is quite possible. We see him distracted at multiple points, an almost sort of ‘coming to’ and trying to figure out where he is and process what’s going on,” she said.

“The other thing that we’re seeing — and we’ve seen some of this behavior in the past couple months — might suggest mania. Meaning hyperactivity, hyper energy, been possibly up and not sleeping for days. What we might be seeing here is the post effects.” Randazzo said a third possibility is that Holmes, a former neuroscience student, is faking mental symptoms he likely learned during his studies.

UPDATE: Looks like Holmes’ actions are just as mysterious as the man himself. ABC’s Denver affiliate now disputes the spitting reports and states that Holmes has maintained his low-key demeanor since incarceration.

“[C]ontrary to what some media organizations have reported, our sources say in the past 48-hours Holmes has been calm and docile in jail, just like he was in court,” CALL7 Investigator John Ferrugia says. “There have been no outbursts at all as he is in isolation.”